Bag packer



H. L. STOKER April 10, 1951 BAG PACKER 3 Sheets-Sheet 5 Filed NOV. 9, 1946 .2 K 5. mm 5 w 4V 7 4 R1. M y

Patented Apr. 10, 1951 UNITED STATES PATENT OFFICE BAG PACKER Henry L. Stoker, Claremont, Calif.

Application November 9, 1946, Serial No. 709,064

9 Claims.

My invention relates generally to packaging machinery and more particularly to bag filling equipment adapted to place a predetermined amount of a finely divided material such as cement, insecticide, grain or other similar material into a bag or sack.

In the packaging of finely divided material such as those mentioned above, it is customary to place a measured quantity of the material in bags or sacks which may then be closed and delivered to the ultimate consumer. It is obviously more eflicient to place the correct amount of material within the bag during the initial filling operation than to fill the bag and then later add or remove material therefrom to secure the proper weight; and consequently various bag filling machines have been developed to deliver a measured quantity of material into the bag. However, in general these prior machines have supported the bag from underneath so that the natural tendency of the bag and the material within it to slump has required the use of flexible spouts or other equipment adapted to compensate for the consequent lowering of the top of the bag. In some instances, the bag has been supported so that the material within it may slump without moving the upper end of the bag downwardly, but this has required the use of bags having a greater cubic content than is necessary for the material to be placed therein. As a result, the bag, when filled, has a certain amount of air space therein which often leads the purchaser to believe that he is not receiving all Of the material to which he is entitled. Furthermore, it has been diflicult in these prior machines to fill bags at a rapid rate without having considerable variations in weight between individual bags.

It is therefore a major object of my invention to provide a bag packer adapted to place a predetermined amount of finely divided material into a bag.

Another object of my invention is to provide such a packer which is designed to fill a bag so that substantially the entire cubic content thereof is filled, leaving a minimum of air space therein.

It is a further object of my invention to provide a packer of this type adapted to fill bags with an accuracy heretofore unobtainable when the filling is done rapidly, as it must be where large numbers of sacks are to .be filled.

Still another object of m invention is to provide a bag packer having improved means toIsecure the uninterrupted flow of material from the hopper to the mechanism delivering the material to the bag.

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It is a still further object of my invention to provide a bag packer possessing these advantages which is simply and ruggedly built, and which is automatic in operation.

These and other objects and advantages of my invention will become apparent from the following description of a preferred form thereof, and from the drawings illustrating that form in which Figure 1 is a side elevational view of a bag packer embodying the features of my invention, with a bag to be filled indicated thereon in phantom outline;

Figure 2 is a partial end elevational view of the front or bag receivingend of the packer;

Figure 3 is an enlarged elevational view oflthe end of the bag filling spout or conduit, showing the bag supporting means;

Figure 4 is a cross-sectional view taken at 4-4 in Figure 2 and showing the interior of the hopper and the construction of the screw conveyor; and

Figure 5 is a plan view of the packer taken at 5-5 in Figure 4.

Referring now to the drawings and particularly to Figures 1 and 4 thereof, it will be seen that my improved bag packer is supported by a frame work ID, preferably formed of'angle or other suitable structural members, and including horizontal or bed members I I supported by a pair of shorter vertical legs l2 at one end thereof, with pairs of longer vertical legs l3 and M at the middle and opposite end thereof. The longer pairs Of vertical legs I3 and I4 are connected together at their upper ends by horizontal members I5, 15a, l6, and Ilia, shown in Figure 5, to form a rectangular supporting framework for a hopper 20. Cross-bracing (not shown), of course, may be provided to secure the necessary rigidity of the framework In as required by the size of the device and the loads it is intended to carry.

The walls of the hopper 20 are angularly disposed so that sidewalls 2] and Ma converge toward a point just below the lower edge of those walls, while end walls 22 and 22a converge downwardly but are nevertheless a considerable distance apart at their lower edges. Material placed in the hopper 20 thus tends to move downwardly toward a worm or screw conveyor 23 centrally located immediately beneath the hopper 20.

The screw conveyor 23 is supported by the framework Ill just-above the horizontal members I] and'parallel tothe axis of the latter. A housing 24 surrounds "the conveyor 23, and is provided with an opening in its upper portion which connects to the hopper 20 so that material in the latter will be delivered to the conveyor without spilling. A coaxial shaft 25 extends throughout the length of the housing 24 and is provided with a screw type worm 26 thereon which is adapted to move material through the housing when the shaft is rotated. At the rear end of the housing 24 I provide a bearing support 21 through which shaft 25 passes, andat the rear end of the latter, prefer ably beyond the vertical leg I2, I mount a pulley 30 or other suitable member adapted to be rotated by a reversible electric motor.

Forward of the longer vertical legs [4, the housing 24 is provided with a constricting porjtiori 3! iii the form of a truncated cone which terminates in a smaller cylindrical section 32.

Since the worm 26 is designed to fill substantially the. entire area of the housing 24, the constriction 3| necessitates a reduction in the outer diameter of the worm at this point, and to maintain the capacity of the. screw conveyor 23 constant throughout its length, the diameter of shaft 25 is likewise reduced at this point.

The. cylindrical portion 32 of the housing 24 is relatively short, and the worm 2e and shaft 25 continue beyond the end of the cylindrical portion and extend into a conduit 33 having a generally oval cross-section. The conduit 33 is spaced a slight distance from the cylindrical portion 32 and is supported for vertical movement. about a pivot point 34. The oval shape of the opening within the conduit 33 permits limited vertical movement of the latter without: causing binding of the worm 2t therein. This clearance between the worm 2e and the interior of the conduit 33 is shown in greatly exaggerated form in Figure 3'- A bag supporting frame 35, is attached to the conduit 33, so that a bag of the well known flap or valve type may be supported from the frame and filled by the discharge of the material through the conduit. 33.

To support the conduit 33 and frame 35, 1 provide a rigid framework 36 which is pivotally attached to the horizontal member H at the previously mentioned; pivot point 3 As clearly seen in Figures 1. and 4, the frame as: is formed as a lever or beam which is adapted to, support a bag at one end, while, the other end extends from. the pivot point 34 toward the shorter vertical leg I 2 and carries a counterweight tl. A pair of stops 40 and M, mounted on the shorter vertical, leg [2, restrain the motion of the beam 36 and permit the latter to act, in conjunction with the, counterweightv 31, as, a balance beam. Thus, when there, is no bag on the supporting frame 35, the. counterweight 31 will move the rear end of the beam, 36 downwardly until it strikes the stop 4], while a bag which has too much material in it will overbalance the counterweight and move the rear end of the beam upwardly until it strike the stop 40. The position of the counterweight 31 is preferably adjustable along the length of the beam 36 so that any predetermined amount of material may be placed in the bag before the latter overbalances the counterweight to move the beam against stop 40.

As previously mentioned, shaft 25 is driven by motor 2.9, and the operation of. the latter is controlled bya. pair of switches 4.2 and 43 mounted on the shorter vertical leg 12 adjacent. thestops 40 and 41;. It. will: be. understood that the switches used for this control will norma y ,1

.drives the shaft 25.

be adapted to carry the heavy current necessary in the operation of the motor, but small switches may be used to operate relays which in turn control the operation of the motor. The circuits controlled by these switches will, of course,

'vary with the type of motor used, and whether or not relays are used, but since such circuits are simple and are well known in the art, they will not be shown or described in detail here.

The switches 62 and 43 may be of any suitable type, but are preferably of the miniature snap action variety so that circuits are quickly made and broken, with a minimum of sparking and burning of the contacts. In addition, the upper and lower switches Q2 and 4 3 are preferably set. a suificient distance apart so that they will not be operated by any bouncing of the beam 36 caused by vibration of the different parts of the bag packer. Switch 43 is connected to.- the motor 29 either directly or through a relay (not shown), to operate the motor so that the shaft 25 is turned to advance material from the hopper 20 into the conduit 33 and then into the bag. Similarly, switch 42 is adapted to operate the motor in the opposite direction so that the material is removed from. the conduit 33 and returned to the hopper. The position of beam 36 thus controls the operation of the bag packer, and by properly locating the counter-'- weight 31, an accurately measured amount of material may be placed in large numbers of bags, with the variation in weight between individual bags being very small.

In the packaging of many finely divided ma-' terials, especially those which have a tendency to absorb, moisture from the air, a serious problem arises in preventing such material fromcaking or packing within the hopper so that the material does not flow freely to the bottom there-' of but instead remains in it so that none or avery small amount of the material is delivered to the worm. 26. To overcome this difiiculty, agi-- tators are frequently installed in hoppers to firevent such packing and to insure the constant flow of material. Most of the prior agitators, however, have. been located in the central portion of the hopper so that while materialin that area has been maintained in a powdered, fluid state, the material near the edge has had an op portunity to pack and clog the hopper. Consequently, i. have developed the agitators shown in Figures 4 and 5 and comprising an oscillatable structure located adjacent the side wallsof the hopper and driven by the same motor which As shown, the agitator structure comprisesv a pair of generally upwardly extending rods 58 and SI extending along the side walls 2! and 21a near the rear and forward wallsv 22a and. 22 respectively. Rods 5,0 and 5f are joined near their mid-section by a generally horizontal rod 52, to which is attached a centrally located rod 53 extending downwardly from it, and a generally H-shaped agitator member 54, with one leg longer than the other, extending upwardly. The various elements of the agitator structure thus follow the general shape of the side walls 2| and 2la, with offsets provided, if needed, as in the lower end of the generally upwardly extending rod 50.

To operate the agitator members, I mount a shaft 55 across the hopper 20 near the upper end thereof, and, support it in bearing members 51 and 510,. the shaft extending through bearing 51 and carrying a crank arm 6!! at its outer end. The bearing members 5'! and 51a, because of the auaovb nature of the material to which they are exposed, are normally provided with dust tight seals which prevent the movement of dust or powder along the shaft 56 into the bearing itself.

The crank arm 60 is driven by a gear box 6| or other suitable driving unit mounted on the vertical legs I3 and driven in any suitable manner, as by belts and pulleys 62, from shaft 25. The output shaft 63 of the gear box 6| is parallel to the transverse shaft 56, and is provided with a rather short crank arm 64 which is pivotally connected by a connecting rod 65 to the free end of crank arm 60. As shaft 63 revolves, therefore, the crank arm 60 will be oscillated to operate the agitator members, and if aseries of pivotal connections for the connecting rod 65 are provided in the end of the crank arm 60, the amplitude or amount of angular movement of the crank arm 60 may be varied to meet different conditions.

Extending downwardly from the shaft 56 within the hopper 20 is a crank arm 66 which is attached to one end of the shaft for rotation with the latter, and between the lower end of the crank arm and the horizontal rod 52 of the agitator mechanism is a pivotally attached connecting rod or link 61. It will be noted that the use of the pivoted link 6'! permits the agitator assembly to be moved horizontally as the crank arm 66 rotates, and thus an agitation is provided for the material within the hopper which prevents its packing and keep it free-flowing. In this connection, the movement of the crank arm 66 aids in this result, but its effect is not so great as that of the agitator assembly proper, since the crank arm is located more nearly in the middle of the hopper where the eifect of packing is less important. A similar crank arm 66 and pivoted link 61 are mounted on the other end of shaft 56 to operate the agitator assembly adjacent side wall 2|, and thus the entire mass of material within the hopper is kept free-flowing at all times.

To stop the flow of material from the hopper 20 to the screw conveyor 23, I provide a movable cover or gate 10 which is adapted to be raised or lowered by a hand operated crank 1|. As indicated in Figure 2, the gate 16 includes a pair of downwardly divergent walls extending substantially parallel to the axis of the conveyor 23, with their ends shaped to conform to the end walls 22 and 22a. The walls of the gate 10 are joined at their upper edges to form a generally triangular structure on which the powdered material will not remain, and the latter thus slides downwardly around the gate 10 to the conveyor 23. It will be realized that the walls of the gate 10 extend outwardly a sufficient distance at their lower ends to bear against the side walls 2| and 2 la of the hopper so that the flow of material from the side walls may be stopped or materially reduced when the gate is in its lowered position.

The relative position of the gate within the hopper 20 is controlled by a longitudinally extending shaft 12 which extends through the hopper and carries the handle 11 on its forward end. Intermediate the end walls 22 and 22a, the shaft 12 is provided with one or more crank arms 13 which rotate with the shaft and are pivotally connected at their lower ends to vertically extending connecting arms 14 whose lower ends are attached to the gate 10. By adjusting the position of handle 1 I, the rate at which material flows from hopper 26 to the conveyor mechanism 23 may thus be controlled, and hence with a given speed of the shaft 25, a bag may be filled rapidly or slowly, as the occasion may demand.

Operation In the operation of my improved bag filling machine, a bag or sack of the valve type is placed over the bag supporting framework 35 so that the bag i clear of all articles or members which might interfere with its movement, and so that the conduit 33 extends within the bag to discharge the material into the latter. The hopper 20 is filled with the desired material, and the counterweight 31 is adjusted so that the proper amount of this material will be placed in the bag. The power circuit for the motor is then energized, and since the big is empty, the counterweight will urge the beam 36 to its lowermost position where switch 43 is operated to drive the motor in such a direction that worm 26 is rotated to advance the material from the hopper 20 to the end of the conduit 33.

As this is bein done, the drive mechanism 62 causes the gear box 6| to rotate the shaft 63 and oscillate the crank arm 60 so that the agitator assembly insures a constant movement of the material. As mentioned, the speed at which the bag will be filled may be controlled by adjusting the handle H to vary the position of the gate 10, and if desired, the speed may be relatively high at first, and then reduced as the bag becomes full, should this be desirable.

When the material within the bag approaches the predetermined weight, the beam assembly 36 approaches a point of balance so that only a slight additional amount of material is necessary to move the beam from its position against the lower stop 4| to the upper stop 40. When this occurs, switches 42 and 43 are operated to stop the forward rotation of the motor, and rereverse it so that the worm 26 now tends to remove the material from the bag. It will be realized, of course, that the'motor and the members driven by it cannot be instantly reversed, and hence there will be a slight amount of overtravel with additional material delivered to the bag. However, the reversal of the direction of rotation of worm 26 will remove a portion of this material if the bag is substantially full, as it normally will be, and the amount of material thus returned will normally be substantially equal to the amount delivered after switch 43 was operated, corresponding to the over-travel of the worm 26. Should it happen that too much material is returned to the hopper 20, the beam 36 will be returned to its first position and additional material will be packed into the bag. However, the amount of material which may be removed by the operation of the worm 26 is generally insufficient to trip the beam in the opposite direction, since the worm is capable of movin very little more of the material than that in the conduit 33. Consequently, the fillin operation will normally cease with the bag filled to a point just suificient to maintain the beam 36 in position against the upper stop 40, and with the motor therefore rotating in the reverse direction but with no more material being removed from the bag by the worm 26. The motor circuit may then be deenergized, and the bag removed from the framework and inverted, whereupon the valve in the bag will be closed to prevent the escape of the material.

By supporting the bag solely from its upper end, the tendency of the bagand the material 7 contained, therein to slump is greatly reduced, and .a smaller bag may be used to contain. the same amount of material, since it is unnecessary to make provision for the upper end of the bag to move downwardly, away from the conduit 33', as the bag. is filled, This pendant suspension permits a smaller bag to be used, and since the latter may be completely filled, the purchaser is visually assured that he is receiving full value. Furthermore, by the. provision of my improved agitator means, I am able to secure a constant flow of material within the hopper at all times, since this agitatin actionis provided along the sides of the hopper where caking and packing are mostlikely to occur and cause the greatest amount of trouble.

From the foregoing, it will be seen that I have provided an improved bag packing machine which is fully capable of achieving the objects andadvantages set forth. While I have shown and described a preferred form of my invention, I do not wish to be limited to the particular form or arrangement of parts herein described and shown, except as covered by my claims.

I claim:

1.. A bag packer adapted to be driven by a motor means, which includes: a hopper adapted to receive a finely divided material; a pivoted beam adapted to receive a bag at one end thereof a conduit attached to said beam for movement therewith and mounted to extend into said bag; reversible motor means; a reversible screw conveyor driven by said motor, extending from said hopper into said conduit to a point adjacent the open end of the latter to move said material from said hopper through said conduit, said conduit being shaped to permit of its movement with respect to said conveyor without binding against the latter; counterbalancing means attached to the opposite end of said beam; and control means adjacent said opposite end of said beam and operated thereby to reverse the rotation of said conveyor means and remove some of the material in said bag when the combined. weight of said bag and said material contained therein exceeds a predetermined amount.

2. A bag packer adapted to be driven by a reversible motor, which includes: a hopper adapted to receive a finely divided material; a. beam pivotally mounted with respect to said hopper; bag supporting means attached to one end, of said beam andadapted to be. inserted in the upper end of said bag; a conduit mounted on said beam adjacent said bag supporting means to extend into said bag, said conduit and said bag supporting means being mounted on said beam formovement therewith; a screw type conveyor extending from the lower end of said hopper into said conduit to a point adjacent the open end of the latter, and adapted to move said material from said hopper into said'bag, said conveyor being held against movement except rotation about its axis, and said conduit being shaped to prevent its. movement from interfering with the operation of said conveyor; stop means adjacent the opposite end. of said beam. and adapted to limit the pivotal motion thereof; a counterweight mounted on said beam to urge the latter against the lower of said stop means; a reversible motor connected to said conveyor, and switch means adjacent said stop means, to control the operation of said motor to drive said, screw conveyor to carry said material from said hopper to said bag whensaid beam is in its. lowermost position, and

to reverse the rotation of said conveyor andv thereby remove some of the material in said bag when the combined weight of said bag and said material contained therein exceeds a predetermined amount and said beam is moved to its upper limiting position.

3. A bag packer adapted to be driven by a reversible motor means and used to fill valve type bags, which includes: a container adapted to receive and hold the material with which said bag is to be filled; a bag supporting framework adapted to be inserted in said bag through the valve thereof to support said bag from its upper end,;whereby said bag is supported solely by said framework; a conduit adapted to extend into said bag with said framework through said valve; weighing means pivotallys'upporting said bag, said framework, and said conduit; a reversible motor means; a conveyor driven by said motor means and extending from said container to a point adjacent the open end of said conduit, adapted to carry said material from said container through said conduit and into said bag; and control means operated by said weighing means to reverse the operation of said conveyor means to remove material from said conduit and said bag when the weight of said bag and the material contained therein and in said conduit exceeds a predetermined amount.

4. A filling device for valve type bags, adapted to be used with a bag packer having a reservoir to receive the material with which the bag is to be filled and a weighing mechanism to control the operation of said filling device, which includes: a framework adapted to extend into said bag through the valve thereof, whereby said bag is supported solely at its upper end by said framework; a conduit adapted to extend into said has through the said valve thereof, said conduitand said framework being attached to said weighing device for movement in a vertical plane; and a screw type conveyor extending from said reservoir through said conduit and rotatable to move said material from said reservoir and through said conduit into said bag, said conveyor bein mounted for rotation about its axis and held I against movement in a vertical plane, the interior of said conduit being shaped to permit free rotation of said conveyor in all positions of said conduit.

5. A bag packer which includes: a hopper adapted to receive material; a conduit adapted to convey material to a bag attachedto the end thereof; a beam. supporting said conduit for limited movement of the latter about a horizontal axis; and a screw conveyor extending from said hopper into said conduit, said screw being rotatable about its axis but otherwise substantially immovable, said conduit being shaped for generally vertical movement with respect to said screw without binding against the latter while maintaining a minimum separation therefrom.

6. A bag packer which includes: a hopper adapted to receive material; a weighing beam adjacent said hopper for limited rotational movement about a generally horizontal axis; a screw conveyor extending generallyhorizontally from said hopper and rotatable about its own axis to move said material from said hopper while said beam moves with respect to said conveyor; and a rigid conduit mounted on said beam and movable therewith for carrying said material into. a

container on the end, of said conduit, said screw conveyor extending into said conduit and having the minimum clearance from, the. interior walls of; the latter necessary for the generally vertical movement of said conduit with respect to said screw conveyor.

7. A bag packer which includes: a hopper for receiving material; a screw conveyor extending generally horizontally from said hopper and rotatable about its axis to transport said material,

said axis remaining substantially fixed and horizontal at all times; a generally horizontal beam mounted for limited rotational movement with respect to said hopper and said screw conveyor about a generally horizontal axis substantially perpendicular to the axis of said beam; and a conduit mounted on one end of said beam for movement therewith and holding the container into which said material is to be packed, said conduit being aligned with and adjacent the shell of said screw conveyor and having the screw thereof extending into said conduit, the interior surface of said conduit being shaped so that the sides thereof are immediately adjacent said screw and the top and bottom are selectively spaced therefrom, whereby said conduit may be rotated a limited amount about said axis of rotation of said beam without binding against said screw.

8. A packer which includes: a hopper adapted to receive material; a generally tubular conduit adapted to convey material to a receptacle at the end thereof; a beam supporting said conduit for limited movement of the axis of said conduit about a horizontal axis; and a rotatable screw conveyor generally coaxial with said conduit, having its axis held against movement with said conduit, extending from said hopper into said conduit, said conduit having an internal shape that prevents its binding against said conveyor as said conduit is moved with respect thereto while maintaining a minimum separation therefrom.

9. A packer which includes: a hopper adapted to receive material; a rotatable screw conveyor extending from said hopper to conduct said material therefrom, said conveyor being rotatable about its axis, but said axis being held against movement; a pivoted beam adjacent said conveyor and movable with respect thereto; and a conduit attached to said beam for movement therewith, surrounding said conveyor and generally coaxial therewith, said conveyor extending from said hopper to a point adjacent the open end of said conduit, the interior of said conduit being shaped to insure the free movement of said conduit with said beam Without binding against said conveyor while maintaining a minimum clearance therefrom.

HENRY L. STOKER.

REFERENCES CITED The following references are of record in the file of this patent:

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